Once emblematic of Montreal’s emboldened vision of itself and its future, the Turcot Interchange continues to suffer a painful demise. As urban planners, environmentalists and community groups speak up, one renowned expert sees it as a valuable opportunity. It’s time to ask how we see Montreal in 50 years, 100 years and well beyond.
A monument to modernity, Montreal’s Turcot Interchange opened in 1966, matching the vibrant, futuristic image created by Expo 67’s international venues and a gleaming new metro system. The Turcot’s concrete spans curved and looped one hundred feet above the ground, goliath-like pillars promising eternal support for its multilevel overpasses and elevated ramps. Within a few short years, it stretched into three major autoroutes, the A-15 (Décarie Expressway), the A-20 (Remembrance Highway), and the A-720 (Ville-Marie Expressway) and even gave access to the Champlain Bridge.
The Turcot served up an exciting vision. Finally, Montreal had contender status as a top-notch metropolis. But, over the past 40-odd years, the Turcot has struggled to maintain that promise. And it shows.
Originally constructed to carry 50,000 to 60,000 vehicles per day, in 2010 it averaged a north-southbound flow of about 278,000 daily drivers and over 350,000 going west-eastbound. Winter road salt has caused corrosion of the steel reinforcement, resulting in extensive deterioration of the structure. As a result, concrete has crumbled and fallen away in large pieces. Pictures present a sad and terrifying image of a highly overused interchange urgently in need of repair.
In 2007, the ministère des Transports du Québec (MTQ) proposed tearing down the Turcot and replacing it with a new ground-level interchange that would handle up to 20 per cent more vehicles. The proposal sparked an ongoing debate and parallels many of the issues raised in the early 60s, though critics – urban planners, environmentalists and citizen groups – heartily agree that something must be done.
The 1970 construction of the Ville-Marie Expressway involved destroying well over 1,000 residences. The MTQ’s 2007 proposed plan called for the expropriation of more than 160 residences, primarily in Saint-Henri’s Village des Tanneries neighbourhood. The new structure, to be built on embankments, would sever links between Saint-Henri, Côte-Saint-Paul and other working-class areas. The ground-level placement of the interchange would also increase noise and air pollution for remaining residents.
Environmental issues
Environmentalists were quick to point out that the MTQ’s plan failed to address the fight against climate change. And although the plan called for reserved bus lanes, it perpetuated the supremacy of commuting by car as illustrated by the MTQ’s expectation that volume on the interchange would increase to 347,000 vehicles per day by 2016.
The MTQ’s plan did reflect their expectation that even with increased volume, ambient pollution would not increase as new cars became more efficient and pollute less. At present, motor vehicles generate about a third of Quebec’s greenhouse gas emissions as well as much of the region’s smog.
Public hearings were held, managed by the Bureau d’audiences publiques sur l’environnement (BAPE), a major focus being information presented in the Environmental Impact Assessment. It recommended the MTQ review its proposal, which it has done.
But the debate continues. The Conseil régional de l’environnement de Montréal (CREM), an environmental lobby group, has argued for a broader debate than that allowed by BAPE. And the Table de Travail Turcot, a group of urban planners, academics and community groups, contends that the government and all parties should understand that the real problem to address is that of mobility within a better designed city.
That’s basically Dr. Saeed Mirza’s view. As Professor Emeritus in Civil Engineering at McGill University and past president of the Canadian Society for Civil Engineering, Mirza’s expertise in structural engineering and infrastructure rehabilitation have singled him out as someone whose opinion counts.
“You should look at the total cost of the project, that means the engineering cost, economic losses and social costs to the community for any reason, and of course, the cost to the environment,” he states.
“The MTQ must think about reducing the Turcot’s current capacity and providing dedicated lanes for transit such as buses and light rapid transit. Unfortunately, the Turcot is now in such a bad state. I’ve seen solutions proposed to shore it up, but the main body is gone, the steel inside has corroded and the concrete is disintegrating. There is no way it will last for a long time even with adding things to keep it standing.”
A clear vision for Montreal
His stance echoes several of those presented in Montréal at the Crossroads: Superhighways, the Turcot and the Environment, a book published in 2009 by a number of Montreal academics, writers and other professionals. As a long-time civil engineer, Mirza advocates a new interchange designed with the entire life-cycle performance in mind, and with a clear vision of a Montreal we would like within the next 50 to 100 years.
The Lethbridge Viaduct, the largest railway structure in Canada, was completed in 1909 and is still in use. As well, the Confederation Bridge, joining Prince Edward Island and New Brunswick, the world’s longest bridge over ice-covered water at 12.9 kilometres (8 miles), was designed to last a century or longer.
A key problem in the late 50s and 60s was that emphasis was on strength of structures rather than the permeability of concrete. It made it easy for salt solutions and salt from snow melt to flow into the concrete.
“We have more knowledge now,” Mirza explains. “We can design concrete with low permeability that allows very little salt solution to enter and ensure that efficient drainage makes it flow away from the structure. In which case, a structure could last 100 years or more. As well, intelligent instrumentation within a structure can indicate exactly how internal deterioration due to ingress of salt is progressing, and how this deterioration can be mitigated and treated.”
Mirza also cites the use of carbon-fiber-reinforced polymers in steel, mentioning a program currently investigating the response of girders to aggressive environments. So design and high quality construction will guarantee a long service life as well as reduced maintenance cost over time.
“We have the solutions, the knowledge, the technology,” Mirza states. “It’s a question of putting it all together. We don’t need to replace old things with similar things. One interchange is just part of the transportation network. We must look at a total transportation network for the Greater Montreal Area for the next 100 years.”
Excerpted from Les carrières de l’ingénierie 2014 (namely Careers in Engineering)